This invention relates to a stent and its implantation into blood vessels. More particular, it relates to a stent and an application catheter used to implant the stent into vascular bifurcations, side branches and ostial lesions.
Stents are prostheses to support the lumen of hollow organs, primarily to acutely maintain the lumen of blood vessels after mechanical interventions such as balloon angioplasty and to achieve a better long term result after such mechanical interventions. While implantation of stents into straight vessel segments poses little technical problems, implantation of stents into ostial lesions, sidebranches or into vessel bifurcations represents a challenge to the operator and carries increased risks of acute and long-term failure, in particular due to misplacement or imprecise placement.
In ostial lesions, the proximal end of the stent must be precisely placed at the ostium of the artery so that the stent is not protruding into the aortic lumen. In order to avoid the above risk, the stent is sometimes advanced too far into the artery causing the initial segment of the diseased ostium to remain unstented.
A similar problem exists with stenting of sidebranches and vessel bifurcations. For both situations, precision placement techniques are required for optimal results. However, the operator must rely on visual assessment during fluoroscopy with and without contrast injections. Contrast injections are of little help for stenting in ostial lesions, since opacification of the target artery is usually inadequate and identification of the aortic lumen and the ostial takeoff is very limited. In sidebranch and bifurcational lesions, precise placement is similarly difficult due to poor identification of the exact beginning of the sidebranch ostium and the often non-perpendicular nature of the plane of the sidebranch in relation to the axis of the major vessel. The beating heart makes maintaining of a catheter position with current techniques even more difficult if not impossible.
The current invention offers a unique solution to the technical problems as described above.
A dilation catheter has a distal exit of a first guidewire channel located distally from an inflatable balloon portion and a distal exit of a second guidewire channel located proximally from the distal exit of the first guidewire channel. The distal exit of the second guidewire channel is located along the inflatable balloon portion or other expandable portion of the dilatation catheter. An oblique ended expandable stent is mounted therearound and used to treat bifurcated and sidebranched arteries and ostial lesions.